Pyrrolidin-3,4-diol derivatives of heptitols and preparation thereof

ABSTRACT

Novel heptitol analogues of mannofuranose and their syntheses from delta -lactones of heptonic acids are disclosed. The novel heptitols are (A) 2,5-dideoxy-2,5-imino-D-glycero-D-talo-heptitol and (b) 1-amino-2,5-anhydro-1-deoxy-D-glycero-D-talo-heptitol. These novel heptitol compounds are useful inhibitors of glycosidases.

BACKGROUND OF THE INVENTION

This invention relates to seven-carbon analogues of mannofuranose and,more particularly, to novel heptitol compounds and their syntheses fromδ-lactones of heptonic acids. These novel heptitol compounds are usefulinhibitors of glycosidases.

Polyhydroxylated nitrogen heterocycles constitute a major class ofglycosidase inhibitors [Winchester and Fleet, Glycobiology2, 199 (1992);G. Legler, Adv. Carbonhydr. Chem. Biochem. 48, 319 (1990)] and may alsoprovide clues to the nature of many carbohydrate recognition processes[Furui et al., Carbohydr. Res. 229 C1 (1992)]; glycosidase inhibitionmay be of value in the study of diabetes [Rhinehart et al., Biochem.Pharmacol. 39, 1537 (1990); Liu, J. Org. Chem. 52 4717 (1987)], cancer[Woynarowska et al., J., Anticancer Res. 12, 161 (1992); Liu et al.,Tetrahedrom Lett. 32, 719 (1991)] and some viral diseases [Jones andJacob, Nature 330, 74 (1991); Taylor et al., AIDS 5, 693 (1991);Stephens et al., J. Virol. 65, 1114 (1991)]. Because of the potentialchemotherapeutic applications of such materials, there is continuinginterest in the synthesis of both monocyclic analogues [ Lees andWhiteside, Bioorg. Chem. 20, 173 (1992); Hassan, Gazz. Chim. Ital. 122,7 (1992); Fairbanks et al., Tetrahedrom 48, 3365 (1992)] and bicyclicanalogues [Burgess and Henderson, Tetrahedrom 48, 4045 (1992); St. Denisand Chan, J. Org. Chem. 57, 3078 (1992); Herczegh et al., TetrahedronLett. 33, 3133 (1992); Gradnig et al., Tetrahedron Let. 32, 4489(1991)]. In particular, the specific inhibition of individual N-linkedglycoprotein processing α-mannosidases by nitrogen analogues ofmannopyranose [Bischoff and Kornfeld, Biochem. Biophys. Res. Commun.125, 324 (1984); Fuhrmann et al., Nature 307, 755 (1984)] andmannofuranose [de Gasperi et al., J. Biol. Chem. 267, 9706 (1992) mayprovide a useful anticancer strategy [White et al., Cancer, Commun. 3,83 (1991); Olden et al., Pharmacol. Ther. 50, 285 (1991)].

BRIEF DESCRIPTION OF THE INVENTION

In accordance with the present invention, novel heptitol analogues ofmannofuranose and their syntheses from δ-lactones of heptonic acids areprovided. These novel heptitol compounds are, respectively, (A)2,5-dideoxy-2,5-imino-D-glycero-D-talo-heptitol, also designated hereinas α-homoDIM (compound 4), and (B)1-amino-2,5-anhydro-1-deoxy-D-glycero-D-talo-heptitol, also designatedherein as α-(aminomethyl)-1-deoxy-mannofuranose (compound 5). Thesenovel heptitol compounds are prepared herein by a novel method ofsynthesis from the acetonides of glycero-talo- andglycero-galacto-heptono-lactone.

The starting δ-lactones of heptonic acids are3,4:6,7-di-O-isopropylidene-D-glycero-D-galacto-heptono-1,5-lactone(compound 7) and3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptono-1,5-lactone(compound 10). These starting compounds are known materials described byBruce et al., Tetrahedron 46(1), 19-32 (1990); Beacham et al.,Tetrahedron Asymmetry 2(9), 883-990 (1991); and by Fleet and Bruce, U.S.Pat. Nos. 5,011,929, 5,101,027, and 5,136,036. They are alsoconveniently prepared from diacetone mannose (compound 6).

The novel heptitol compounds of this invention are useful inhibitors ofglycosidases. Their activity is demonstrated herein against elevendifferent types of human liver glycosidases by a conventional enzymeassay method described by Cenci di Bello et al., Biochem. J. 259,855-861 (1989). Although the novel α-homoDIM (4) can be consideredstructurally as a derivative of the known α-mannosidase inhibitor,deoxymannojirimycin (DMJ, compound 1), in which an anomericα-hydroxymethyl group has been added to a polyhydroxylated pyrrolidinering, it unexpectedly is about twice as effective as DMJ in itsinhibitory activity against α-mannosidase but much less potent in itsinhibitory activity against α-fucosidase. On the other hand, the novelα-(aminomethyl)-1-deoxy-mannofuranose (5) unexpectedly is a moderateinhibitor of α-fucosidase but relatively inactive againstα-mannosidases. As such, the novel heptitol compounds of this inventionare also useful in enzyme assays employing α-mannosidase or α-fucosidaseenzyme catalyzed reactions.

DETAILED DESCRIPTION OF THE INVENTION

The invention is conveniently illustrated by the following descriptionof preferred embodiments in which compounds are shown both by chemicalstructure and by compound numbers in parentheses. Reference cited in thedetailed description of the invention are listed at the end. ##STR1##

Syntheses of α-homoDIM (4) and α-(aminomethyl)-1-deoxy-mannofuranose (2)

Both materials were synthesized from the seven-carbon epimeric alcohols(7) and (10), both of which are obtained from the Kiliani ascension¹³ ofdiacetone mannose (6) [Scheme 1]. The tetrahydrofuran ring in (5) isformed by displacement of a leaving group from C-2 of the sugar by thelactone ring oxygen with inversion of configuration at C-2 and retentionof configuration at C-5. The pyrrolidine ring in (4) is formed byintroduction of nitrogen with retention of configuration at C-2 of thealcohol (10) [the major product of the Kiliani reaction], followed byjoining the nitrogen function at C-2 to C-5 with overall retention ofconfiguration, achieved by a double inversion of configuration at C-5; asomewhat analogous strategy has been used for the construction of thepyrrolidine ring in the syntheses of DIM (3)¹² and of diastereomers ofthe bicyclic alkaloid, alexine.¹⁴ ##STR2##

For the syntheses of the tetrahydrofuran analogue (5) [Scheme 2], thegalacto-alcohol (7) was treated with mesyl chloride in pyridine to givethe mesylate (8) [83% yield], together with a small amount of themesylate epimeric at C-2 of the lactone. The key step in the synthesisis a ring contraction reaction of the mesylate (8) induced by methoxide,in which the leaving group at C-2 is displaced by the ring oxygenfunction; addition of solid potassium carbonate to a methanolic solutionof the mesylate (8) resulted in an efficient ring contraction to thetetrahydrofuran ester (12) [81% yield]. This transformation proceeds bynucleophilic addition of methoxide to the lactone carbonyl, ring openingand subsequent ring closure by nucleophilic displacement of the mesylateby the C-5 oxygen function; the overall stereochemical result of thissequence is inversion of configuration at C-2 of the sugar. The iodide(9) may be prepared from the major product (10) of the Kilianiascension; conversion of the alcohol (10) to the corresponding triflatefollowed by treatment with tetrabutyl ammonium iodide give the iodide(9) in quantitative yield. This iodide (9) on treatment with potassiumcarbonate in methanol underwent a similarly efficient ring contractionto give the methyl ester (12) in 80% yield. This general reaction ofδ-lactones with α-leaving groups provides a powerful strategy for thesynthesis of tetrahydrofurans with carbon substituents at C-2 and C-5¹⁵.##STR3##

Subsequent functional group manipulations on (12) gave the furananalogue (5). The ester (12) was reduced by lithium aluminum hydride inether to the primary alcohol (13) [83% yield] which was esterified bymesyl chloride in pyridine to afford the mesylate (14) [95% yield].Nucleophilic displacement of the mesylate function in (14) by sodiumazide in dimethylformamide gave the corresponding azide (15) [51% yield]from which the isopropylidene protecting groups were removed bytreatment with aqueous trifluoroacetic acid to give the azidotetraol(16) [75% yield]. Subsequent hydrogenation of the azide (16) in methanolin the presence of palladium gave the required aminomethyl furanoseanalogue (5), isolated as the crystalline hydrochloride [88% yield-18%overall yield for either the six steps from (7)or the seven steps from(10)].

For the synthesis of α-homoDIM (4) [Scheme 3], the alcohol (10) wasconverted, with overall retention at C-2, to the azide (11) aspreviously described.¹⁶ Attempts at the direct reduction of theazidolactone (11) to the azidodiol (18) were unsuccessful; accordinglythe lactone (11) was reduced first by diisobutylaluminum hydride to thelactol (17) which, on subsequent treatment with sodium borohydride, gavethe required diol (18) [78% overall yield]. The primary hydroxyl groupwas protected as the diphenyl-tert-butylsilyl ether (19) [92% yield]which on treatment with mesyl chloride in pyridine gave theazidomesylate (20) [90%]. Selective hydrolysis of the terminal acetonidein (20) with aqueous acetic acid gave the monoacetonide (21) [79% yield]together with a small amount of the completely deprotected tetraol [4%yield]. Treatment of the dihydroxymesylate (21) with barium methoxidegave the epoxide (22) [84% yield]. Hydrogenation of (22) gave relativelycomplex mixtures; accordingly, the primary hydroxyl group in (22) wasprotected as the tert-butyldimethylsilyl ether (23) [84% yield] which onhydrogenation in ethanol in the presence of palladium black gave theprotected pyrrolidine (24) in 75% yield. Removal of both silylprotecting groups and also of the isopropylidene group from (24) wasachieved by aqueous trifluoroacetic acid to give α-homoDIM (4) [78%yield] as the crystalline hydrochloride salt [21% overall yield from theazidolactone (11)]. ##STR4##

Glycosidase Inhibition

Human liver glycosidases were assayed in the absence and presence [1 mM]of each of the potential inhibitors, using the appropriate buffered4-methylumbelliferyl glycosides as substrates, as previouslydescribed.¹⁷ See Table I, below. The seven-carbon compounds (2) and (4)can be considered as derivatives of the mannopyranose analogue, DMJ (1),and the mannofuranose analogue, DIM (3), in which an anomericα-hydroxymethyl group has been introduced into the unsubstituted carbonatom of the ring. The addition of the anomeric substituent to DMJ doesnot affect appreciably the inhibition of the multiple forms ofα-mannosidase, but it does abolish the moderate inhibition ofβ-hexosaminidase and decrease markedly the potent inhibition ofα-fucosidase (Table). α-HomoDMJ (2) is thus a much more selectiveinhibitor of α-mannosidases than is the parent compound DMJ (1). Theloss of inhibition of β-hexosaminidase can probably be attributed to thehydrophilic nature and incorrect configuration of the hydroxymethylsubstituent; in general, analogues with hydrophobic groups on theanomeric carbon or the ring nitrogen bind more strongly tohexosaminidase. The decrease in inhibition of α-fucosidase can beunderstood by comparing the structure of α-homoDMJ with otherderivatives of DMJ that inhibit α-fucosidase.¹⁸ Both DMJ (1) andα-homoDMJ possess the minimum structural requirement for the inhibitionof α-fucosidases by polyhydroxylated piperidines, that is the correctabsolute configuration of the three secondary hydroxyl groups is thesame for both D-mannose and L-fucose. ##STR5##

    TABLE 1      % Inhibition of Glycosidase Activity at 1 mM concentration of inhibitor      Inhibitor      ##STR6##      ##STR7##      ##STR8##      ##STR9##      Enzyme DMJ (1) αHomoDMJ (2) DIM (3) α     HomoDIM (4) Manhepamine (5)       α     Mannosidase      Lysosomal 58 49  97 K.sub.i 13 μM 71 2  Neutral 30     33  89 76 2  Golgi 45 56  96 92 not determined      β                   Mannosidase  0 0  0 18 3      α              Glucosidase 21 4  0 12 0      β                   Glucosidase  0 0 16 23 14      α            Galactosidase  0 0  0 11 0      β                   Galactosidase  0 0 76 35 0      β             Hexosaminidase 55 1 28  0 46      α               Fucosidase 92 K.sub.i 5 μM 29  24 27 77     β     Glucuronidase 53 0  9  0 7      α                                      Arabinosidase  5 0 66 25 0      β     Xylosidase      3 0 45 21 6

Although α-L-fucosidase is inhibited strongly by some compounds whichhave either a different substituent to the methyl group of fucose or asubstituent with the incorrect configuration at the anomeric position,incorrect substituents at both positions lead to a significant loss ofinhibition even though the configuration of the secondary hydroxylgroups is correct.

The mannofuranose analogue DIM (3) is a much more potent inhibitor thanthe piperidine analogues (1) and (2) of all the mannosidasesinvestigated. The introduction of the anomeric hydroxymethyl group togive α-HomoDIM (4) decreases the inhibition of the lysosomal and neutralenzymes, but not of the Golgi α-mannosidase. These results confirm thatthe binding of aminosugars to α-mannosidases does not require ananomeric substituent; the introduction of the substituent changes therelative specificity of the inhibitor while still retaining significantinhibitory properties towards α-mannosidases. thus the homologues (2)and (4) may allow the further development of substituents in theanomeric position which are specific inhibitors for individualprocessing α-mannosidases. None of nitrogen heterocycles (1)-(5) inhibitβ-mannosidase, suggesting this enzyme has a strict requirement for aβ-anomeric substituent in order to bind strongly.

The tetrahydrofuran derivative (5), which is related to α-HomoDIM (4) byinterchanging the ring nitrogen and the exocyclic oxygen, did notinhibit any of the α-mannosidases, indicating the need of the ringnitrogen to be protonated rather than an exocyclic amine. The structuralbasis for the moderate inhibition of α-fucosidase by (5) is unobviousand is interesting in view of the recent report¹⁹ of the inhibition of amammalian α-fucosidase by the furanose analogue of deoxyfuconojirimycin.The amino group on the anomeric substituent of (5) is probablyresponsible for the weak inhibitory properties towardsβ-N-acetylhexosaminidase.

In a preferred embodiment of the synthesis ofα-(aminomethyl)-1-deoxy-mannofuranose (5) from the galacto-lactone (7),the following reaction steps are carried out:

a. reacting3,4:6,7-di-O-isopropylidene-D-glycero-D-galacto-heptono-lactone (7) withmesyl chloride to give the corresponding mesylate (8),

b. reacting the mesylate (8) with potassium carbonate to produce ringcontraction to the tetrahydrofuran ester (12) with inversion ofconfiguration at C-2,

c. reducing the tetrahydrofuran ester (12) with lithium aluminum hydrideto give the primary alcohol (13),

d. esterifying the primary alcohol (13) at C-1 with mesyl chloride toafford the mesylate (14),

e. displacing the mesylate function in mesylate (14) with alkali metalazide, e.g., sodium azide, to give the corresponding azide (15),

f. removing the isopropylidene protecting groups from azide (15) by acidhydrolysis, e.g., with trifluoroacetic acid, to give the correspondingazidotetraol (16), and

g. subjecting the azidotetraol (16) to palladium catalyzed reductivehydrogenation to form the desired α-(aminomethyl)-1-deoxy-mannofuranose.

Alternatively, the tetrahydrofuran ester (12) used in the foregoingsynthesis can be prepared from the talo-lactone (10) by the followingreaction steps:

a. reacting3,4:6,7-di-O-isopropylidene-D-glycero-D-galacto-heptono-lactone (10)with trifluoromethanesulfonic anhydride to give the correspondingtriflate followed by treating with iodide salt, e.g., tetrabutylammonium iodide, to give the iodide (9),

b. reacting the iodide (9) with potassium carbonate to produce ringcontraction to the tetrahydrofuran ester (12) with inversion ofconfiguration at C-2.

In a preferred embodiment of the synthesis of α-homoDIM (4), thetalo-lactone (10) is esterified with triflic anhydride followed bytreatment with alkali metal azide, e.g., sodium azide, to give theazidolactone (11) as described by Bruce et al., Tetrahedron 46, 19-32(1990) and by Fleet and Bruce, U.S. Pat. No. 5,011,929. The followingreaction steps are then carried out for the synthesis of α-homoDIM fromthe previously known azidolactone (11):

a. reducing2-azido-2-deoxy-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptono-1,5-lactone(11) by di-isobutylaluminum hydride to the corresponding lactol (17),

b. reacting the lactol (17) with alkali metal borohydride, e.g., sodiumborohydride, to provide ring opening and give the diol (18),

c. reacting the diol (18) with tert-butyldiphenylsilylchloride toprotect the primary hydroxyl group as the tert-butyldiphenylsilyl ether(19),

d. esterifying the hydroxyl of the tert-butyldiphenylsilyl ether at C-5with mesyl chloride to give the azidomesylate (20),

e. selectively hydrolyzing the terminal acetonide in the azidomesylate(20) with organic acid, e.g., acetic acid, to give the monoacetonide(21),

f. treating the monoacetonide (21) with barium methoxide to give theepoxide (22),

g. reacting the epoxide (22) with tert-butyldimethylsilylchloride toprotect the primary hydroxyl group as the tert-butyldimethylsilyl ether(23),

h. hydrogenating the tert-butyldimethylsilyl ether (23) in the presenceof palladium black to give the protected pyrrolidine (24),

i. removing all the hydroxyl protecting groups in the protectedpyrrolidine (24) by acid hydrolysis, e.g., with trifluoroacetic acid, togive the desired α-homoDIM.

Other such suitable reactants for use in the foregoing syntheses of theα-(aminomethyl)-1-deoxy-mannofuranose and the α-homoDIM will be apparentto the person skilled in the art after reading the present disclosure.These reactants are generally used in proportions such as to satisfy thestoichiometry of the above reaction steps and shown in the abovereaction schemes 1, 2 and 3. Illustrative of such suitable reactants arethe use of sodium azide, potassium azide, lithium azide andtetrabutylammonium azide to introduce the azide function; use ofhydroxyl protecting groups formed from ketones, dialkylketones andcycloalkylketones to provide groups such as isopropylidene andcyclohexylidene; use of sodium borohydride, potassium borohydride andborane-dimethyl sulfide as reducing agents; use of noble metal catalystssuch as Pd and Pt on carbon for catalytic hydrogenation; use ofelectrophiles such as triflic anhydride, tosyl chloride, benzyl sulfonylchloride and mesyl chloride for the esterification of hydroxyls; and useof organic solvents such as dioxane, DMF, DMSO, THF,N-methylpyrrolidine, pyridine, acetonitrile and the like as solventmedia for the reaction steps. The use of these and other such reactantsin the syntheses of the present invention will be apparent to the personskilled in the art after reading the disclosure herein.

The following examples will further illustrate the invention in greaterdetail although it will be appreciated that the invention is not limitedto these specific examples or the detailed process conditions recitedtherein which are provided by way of exemplification and not limitation.

EXAMPLES General Procedures

Melting points were recorded on a Kofler hot block and are uncorrected.Proton nuclear magnetic resonance (δ_(H)) spectra were recorded onVarian Gemini 200 (200 MHz) or Bruker WH 300 (300 MHz) spectrometers. ¹³C Nuclear magnetic resonance (δ_(C)) spectra were recorded on a VarianGemini 200 (50 MHz) spectrometer and multiplicities were assigned usingDEPT sequence. ¹³ C spectra run in D₂ O were referenced to methanol(δ_(C) 49.6 ppm) as an internal standard. All chemical shifts are quotedon the δ-scale. Infra-red spectra were recorded on a Perkin-Elmer 781 oron a Perkin-Elmer 1750 FT spectrophotometer. Mass spectra were recordedon VG Micromass ZAB 1F, Masslab 20-250 or Trio-1 GCMS (CG-5 column)spectrometers using desorption chemical ionisation (NH₃, DCI) orchemical ionisation (NH₃, CI), as stated. Optical rotations weremeasured on a Perkin-Elmer 241 polarimeter with a path length of 1 dm.Concentrations are given in g/100 ml. Microanalyses were performed bythe microanalysis service of the Dyson-Perrins Laboratory. Thin layerchromatography (t.l.c.) was carried out on aluminium sheets coated with60F₂₅₄ silica or glass plates coated with silica Blend 41. Plates weredeveloped using a spray of 0.2% w/v cerium (IV) sulphate and 5% ammoniummolybdate in 2M sulphuric acid or 0.5% ninhydrin in methanol (foramines). Flash chromatography was carried out using Sorbsil C60 40/60silica. Ion exchange columns were packed with `Dowex` 50W-X8 resin inthe H⁺ form. Solvents and commercially available reagents were dried andpurified before use according to standard procedures; dichloromethanewas refluxed over and distilled from calcium hydride, methanol wasdistilled from magnesium methoxide, pyridine was distilled from, andstored over, potassium hydroxide; tetrahydrofuran was distilled, undernitrogen, from a solution dried with sodium in the presence ofbenzophenone. Hexane was distilled at 68° C. before use to removeinvolatile fractions. The epidermic alcohols (7) and (10) were obtainedfrom diacetone mannose;¹⁴ the azide (11)¹⁹ and iodide (9)¹⁷ wereprepared from (10). Deoxymannojirimycin (1)¹² and DIM (3)¹³ weresynthesised as previously described.

Synthesis of α-(aminomethyl)-1-deoxy-mannofuranose (5) Example 1

3,4:6,7-Di-O-isopropylidene-2-O-methanesulphonyl-D-glycero-D-galacto-heptono-1,5-lactone(8). Methane-sulphonyl chloride (2.6 ml, 26 mmol) was added dropwiseover 2 min to a stirred solution of the galacto-lactone (7) (3.0 g, 10mmol) in dry pyridine (5 ml) at 0° C. under nitrogen. After a further 3h, ¹ H NMR of the crude reaction mixture indicated that no startingmaterial remained. The solvent was removed in vacuo , and the residuedissolved in chloroform (50 ml), washed with dilute hydrochloric acid(3×30 ml), water (2×30 ml), brine (2×20 ml) and dried (magnesiumsulphate). The solvent was removed in vacuo and the residue purified byflash chromatography (ether:hexane, 1:1) to give3,4:6,7-di-O-isopropylidene-2-O-methanesulphonyl-D-glycero-D-galacto-heptono-1,5-lactone(8) (2.49 g, 83%) m.p. 136°-137° C. (Found: C, 45.72; H, 6.16. C₁₄ H₂₂O₉ S requires C, 45.89; H, 6.05%); [α]_(D20) +67.4° (c 1.0 inCHCl₃);δ_(H) (CDCl₃) 1.40, 1.44, 1.48 (12H, 3×s, 4×Me), 3.15 (3H, s,--SO₂ Me), 4.11 (1H, dd, H-7, J₆,7 3.9 Hz, J₇,7' 9.3 Hz), 4.17 (1 H, dd,H-7', J₆,7' 5.6 Hz), 4.41 (1H, ddd, H-6, J₅,6 8.3 Hz), 4.48 (1Y, dd,H-5, J₄,5 1.5 Hz), 4.70 (1H, dd, H-4, J₃,4 7.4 Hz), 4.78 (1H, dd, H-3,J₂,3 2.3 Hz), 5.02 (1H, d, H-2); δ_(C) (CDCl₃) 23.9, 24.8, 25.6, 26.8(4×q, 4×Me), 38.6 (q, --SO₂ Me), 66.4 (t, C-7), 70.5, 72.7, 73.4, 74.2,76.8 (5×d, C-2, C-3, C-4, C-5, C-6), 110.1, 111.2 (2×s, 2×CMe₂), 163.6(s, C-1); m/z (NH₃, DCI) 384 (M+NH₄₊, 100%), 367 (M+H⁺, 80%). A smallamount of the mesylate epimeric at C-2 (0.19 g, 5%) was also formed.

Example 2

Methyl2,5-anhydro-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptaonat (12)(i) From mesylate (8): Potassium carbonate (1.10 g, 7.93 mmol) was addedto a solution of the mesylate (8) (2.90 g, 7.93 mmol) in dry methanol(25 ml) and the reaction mixture stirred at room temperature. After 4 h,t.l.c. (hexane:ethyl acetate, 1:1) indicated complete conversion of thestarting material (R_(f) 0.7) to a single product (R_(f) 0.8). Thesolution was filtered and the solvent removed in vacuo. The residue waspurified by flash chromatography (hexane:ethyl acetate, 4:1) to givemethyl2,5-anhydro-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptonate (12)(1.94 g, 81%) m.p. 79°-80° C. (Found: C, 55.91; H, 8/45. C₁₄ H₂₂ O₇ Srequires C, 55.64; H, 7.34%); [α]_(D20) -11.4° (c 1.0 in CHCl₃); δ_(H)(CDCl₃) 1.36, 1.39, 1.46, 1.52 (12H, 4×s, 4×Me), 3.77 (3H, s, --CO₂ Me),4.01 (1H, dd, H-5, J₄,5 3.7 Hz, J₅,6 7.9 Hz), 4.11 (1H, dd, H-7, J₆,75.6 Hz), 4.14 (1H, dd, H-7', J₆,7' 5.8 Hz), 4.41 (1H, dt, H-6), 4.56(1H, br s, H-2), 4.81 (1H, dd, H-4, J₃,4 6.0 Hz), 4.97 (1H, dd, H-3,J.sub. 2,3 0.7 Hz); δ_(C) (CDCl₃) 24.5, 24.9, 25.8, 26.6 (4×q, 4×Me),52.1 (q, --CO₂ Me), 66.9 (t, C-7), 72.9, 80.4, 82.8, 84.1 (5×d, C-2,C-3, C-4, C-5, C-6) 109.3, 113.3 (2×s, 2×Cme₂), 1.70.7 (s, C-1); m/z(NH₃, CI) 320 (M+NH₄₊, 10%), 303 (M+H⁺, 100%).

(ii) from iodide (9): Potassium carbonate (56 mg, 0.40 mmol) was stirredwith a solution of the iodide (9) (0.16 g, 0.40 mmol) in methanol (20ml) at room temperature. After 4 h, t.l.c. (hexane:ethyl acetate, 1:1)indicated complete conversion of the starting material (R_(f) 0.8) to asingle product (R_(f) 0.7). The solution was filtered and the solventremoved in vacuo. The residue was purified by flash chromatography(hexane:ethyl acetate, 4:1) to give methyl2,5-anhydro-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptonate (12)as a colourless crystalline solid (97 mg, 80%), m.p. 79°-80° C.,identical by ¹ H NMR to that obtained above from the mesylate (8).

Example 3

2,5-Anhydro-3,5:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol (13).Lithium aluminium hydride (95.0 mg, 2.49 mmol) was added in smallportions to a solution of the ester (12) (0.50 g, 1.66 mmol) in dryether (5 ml) and the reaction mixture stirred at 0° C. under nitrogen.After 20 min, t.l.c. (hexane:ethyl acetate, 1:1) indicated completeconversion of the starting material (R_(f) 0.8) to a single product(R_(f) 0.3). The reaction was quenched by the addition of sodiumfluoride (0.10 g, 1.66 mmol) and a few drops of water. The reactionmixture was filtered, the solvent removed in vacuo, and the residuepurified by flash chromatography (hexane:ethyl acetate, 3:1) to give2,5-anhydro-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol (13)(0.38 g, 83%) a colourless crystalline solid, m.p. 82°-83° C. (Found: C,57.02; H, 8.37. C₁₃ H₂₂ O₆ requires C, 56.92; H, 8.08%); [α]_(D20) -6.9°(c 1.0 in CHCl₃); δ_(H) (CDCl₃) 1.36, 1.39, 1.46, 1.52 (12H, 4×s, 4×Me),1.83 (1H, br s, OH), 3.63 (2H, br d, H-1, H-1', J 5.0 Hz), 3.99 (1H, dd,H-5, J₄,5 3.9 Hz, J₅,6 7.1 Hz), 4.07 (1H, dd, H-7, H₆,7 5.0 Hz, J₇,7'8.8 Hz), 4.11 (1H, dd, H-7', J₆,7' 6.3 Hz), 4.17 (1H, br t, H-2), 4.40(1H, m, H-6), 4.68 (1H, dd, H-3, J₂,3 1.3 Hz, J₃,4 6.1 Hz), 4.81 (1H,dd, H-4); δ_(C) (CDCl₃) 24.4, 24.9, 25.9, 26,6 (4×q, 4×Me), 62.0, 66.4(2×t, C-1, C-7), 73.7, 81.0, 81.3, 82.5, 84.8 (5×d, C-2, C-3, C-4, C-5,C-6), 109.0, 112.8 (2×s, 2×Cme₂); m/z (NH₃, CI) 292 (M+NH₄₊, 5%), 275(M+H⁺, 80%), 217 (100%).

Example 4

2,5-Anhydro-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol (14).Methanesulphonyl chloride (1.18 ml, 11.8 mmol) was added dropwise over 2min to a stirred solution of the taloheptitol (13) (1.40 g, 4.0 mmol) indry pyridine (5 ml) and dichloromethane (5 ml) at 0° C. under nitrogen.After a further 30 min, t.l.c. (hexane:ethyl acetate, 1:1) indicatedcomplete conversion of the starting material (R_(f) 0.3) to a singleproduct (R_(f) 0.6). The solvent was removed in vacuo, the residuedissolved in chloroform (50 ml), washed with dilute hydrochloric acid(3×30 ml), water (2×30 ml), brine (2×20 ml) and dried (magnesiumsulphate). The solvent was removed in vacuo and the residue purified byflash chromatography (ether:hexane 1,:1) to give2,5-anhydro-3,4:6,7-di-O-isopropylidene-1O-methanesulphonyl-D-glycero-D-talo-heptitol(14) (1.70 g, 95%), a colourless crystalline solid, m.p. 102° C. (Found:C, 47.89; H, 7.04. C₁₄ H₂₄ O₈ S requires C, 47.72; H, 6.87%); [α]_(D20)-5.9° (c 1.0 in CHCl₃); δ_(H) (CDCl₃) 1.33, 1.39, 1.45, 1.48 (12H, 4×s,4×Me), 3.06 (3H, s, --SO₂ Me), 3.59 (1H, dd, H-5, J₄,5 3.3 Hz, J₅,6 7.3Hz), 3.88 (1H, m, H-2), 4.04 (1H, dd, H-7, J₆,7 4.7 Hz, J₇,7' 8.7 Hz),4.10 (1H, dd, H-7', J₆,7' 6.0 Hz), 4.40 (1H, dd, H-1, J₁,1' 11.2 Hz,J₁,2 7.1 Hz), 4.41 (1H, m, H-6), 4.50 (1H, dd, H- 1', J_(1'),2 4.5 Hz),4.76 (1H, dd, H-3, J₂,3 3.5 Hz, J₃,4 6.1 Hz), 4.80 (1H, dd, H-4); δ_(C)(CDCl₃ ) 24.2, 25.0, 25.5, 26.7 (4×q, 4×Me), 37.3 (q, --SO₂ Me), 66.6,67.8 (2×t, C-1, C-7), 72.8, 79.0, 80.4, 80.5, 82.0 (5×d, C-2, C-3, C-4,C-5, C-6), 109.2, 113.1 (2×s, 2×CMe₂); m/z (NH₃, DCI) 370 (M+NH₄₊, 15%),353 (M+H⁺, 100%).

Example 5

2,5-Anhydro-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol (15).Sodium azide (0.98 g, 15 mmol) was added to a solution of the mesylate(14) (1.70 g, 4.8 mmol) in dry DMF (10 ml) and the reaction mixturestirred at 40° C. After 24 h, t.l.c. (ethyl acetate:hexane, 3:1)indicated partial conversion of the starting material into a singleproduct. The solvent was removed in vacuo and the residue dissolved indichloromethane, washed with water (3×20 ml) and dried over magnesiumsulphate. The product was separated from the remaining starting materialby flash chromatography (ether:hexane, 1:1) to give2,5-anhydro-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol (15),(0.66 g, 44%, 51% based on recovered starting material), a colourlesscrystalline solid, m.p. 69° C. (Found: C, 52.35; H, 7.35; N, 13.97. C₁₃H₂₁ O₅ N₃ requires C, 52.17; H, 7.07; N, 14.07%); [α]_(D20) -7.1° (c 1.0in CHCl₃); ν_(max) (KBr disc) 2093 (N₃) cm⁻¹ ; δ_(H) (CDCl₃) 1.36, 1.39,1.46, 1.52 (12H, 4×s, 4×Me), 3.25 (1H, dd, H-1, J₁,1' 12.9 Hz, J₁,2 4.7Hz ), 3.45 (1H, dd, H-1', J_(1'),2 6.6 Hz), 3.95 (1H, dd, H-5, J₄,5 3.8Hz, J₅,6 7.5 Hz), 4.06 (1H, dd, H-7, J₆,7 4.7 Hz, J₇,7' 8.8 Hz), 4.11(1H, dd, H-7', J₆,7' 6.0 Hz), 4.24 (1H, br t, H-2), 4.40 (1H, ddd, H-6),4.65 (1H, dd, H-3), J₂,3 1.3 Hz, J₃,4 6.1 Hz), 4.82 (1H, dd, H-4); δ_(C)(CDCl₃) 24.5, 24.9, 26.0, 26.7 (4×q, 4×Me), 51.3, 66.7 (2×t, C-1, C-7),73.3, 81.0, 81.6, 83.2, 83.6 (5×d, C-2, C-3, C-4, C-5, C-6), 109.3,113.1 (2×s, 2×CMe₂); m/z (NH₃, DCI) 317 (M30 NH₄₊, 5%), 300 (M+H⁺,100%).

Example 6

2,5-anhydro-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol (16).The azide (15) (0.52 g, 1.72 mmol) was stirred in trifluoroaceticacid:water, 1:1 (5 ml) at room temperature. After 2 h, t.l.c. (5%methanol in ethyl acetate) indicated complete conversion of the startingmaterial (R_(f) 1.0) to a single product (R_(f) 0.3). The solvent wasremoved in vacuo, and the co-evaporated with toluene (3×10 ml) to removethe last traces of acid. The residue was taken up in methanol andpreabsorbed on to silica before purification by flash chromatography (1%methanol in ethyl acetate) to give2,5-anhydro-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol (16)(0.28 g, 75%), m.p. 86° C. (Found: C, 38.18; H, 6.09; N, 18.89. C₇ H₁₃O₅ N₃ requires C, 38.36; H, 5.98; N, 19.17%) [α]_(D20) +71.5° (c 1.0 inCHCl₃); ν_(max) (KBr disc) 2108 (N₃) cm⁻¹ ; δ_(H) (CD₃ OD) 3.25 (1H, dd,H-1, J₁,1' 13.2 Hz, J₁,2 5.2 Hz), 3.51 (1H, dd, H-1', J_(1'),2 2.7 Hz),3.55 (1H, dd, H-7, J₆,7 6.0 Hz, J₇,7 11.5 Hz), 3.77 (1H, dd, H-7', J₆,7'3.0 Hz), 3.86 (1H, dd, H-5, J₄,5 3.0 Hz, J₅,6 8.5 Hz), 3.90-3.93 (2H, m,H-2, H-6), 4.08 (1H, dd, H-3, J₂,3 8.4 Hz, J₃,4 4.1 Hz), 4.20 (1H, dd,H-4); δ_(C) (CD₃ OD) 5.29, 64.5 (2×5, C-1, C-7), 70.9, 72.7, 74.3, 81.1,81.5 (5×d, C-2, C-3, C-4, C-5, C-6); m/z (NH₃, DCI) 237 (M+NH₄₊, 100%),220 (M+H⁺, 20%).

Example 7

α-(Aminomethyl)-1-deoxy-mannofuranose[1-Amino-2,5-anhydro-1-deoxy-D-glycero-D-talo-heptitol hydrochloride](5). The azide (16) (0.12 g, 0.63 mmol) was stirred in methanol (5ml) atroom temperature under hydrogen in the presence of 10% palladium oncarbon (10 mg). After 24 h, t.l.c. (5% methanol in ethyl acetate)indicated conversion of the starting material (R_(f) 0.3) to a singleproduct (R_(f) 0.0). The reaction mixture was filtered through celite,the solvent removed in vacuo, and the resulting solid purified by ionexchange chromatography with Dowex 50W-X8 using 0.5M ammonia as eluant.After freeze drying,1-amino-2,5-anhydro-1-deoxy-D-glycero-D-talo-heptitol (5) (95 mg, 88%)was obtained as a yellowish solid. The solid was taken up in water, andthe solution neutralised with dilute aqueous hydrochloric acid. Freezedrying, followed by recrystalisation from methanol/chloroform, gave1-amino-2,5-anhydro-1-deoxy-D-glycero-D-talo-heptitol hydrochloride (5)as a colourless crystalline solid, m.p. 189° C. (dec.). (Found: C,36.61; H, 7.27; N, 5.42. C₇ H₁₆ O₅ NCl requires C, 36.61; H, 7.02; N,6.10%); [α]_(D20) +38.6° (c 1.0 in CHCl₃); δ_(H) (D₂ O) 3.00 (1H, dd,H-1, J₁,1' 13.4 Hz, J₁,2 8.8 Hz), 3.18 (1H, dd, H-1', J_(1'),2 2.9 Hz),3.52 (1H, dd, H-7, J₆,7 5.0 Hz, J₇,7' 12.1 Hz), 3.66 (1H, dd, H-7',J₆,7' 2.7 Hz), 3.80 (1H, ddd, H-6, J₅,6 9.0 Hz), 3.87 (1H, dd, H-5, J₄,52.6 Hz), 3.91 (1H, dt, H-2, J₂,3 8.4 Hz), 4.05 (1H, dd, H-3, J₃,4 4.1Hz), 4.17 (1H, dd, H-4); δ_(C) (D₂ O) 41.8, 63.1 (2×t, C-1, C-7), 69.0,71.6, 74.3, 77.2, 79.6 (5×d, C-2, C-3, C-4, C-5, C-6); m/z (NH₃, DCI)194 (M+H⁺, 100%).

Synthesis of α-HomoDIM (4) Example 8

2-Azido-2-deoxy-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptose(17). Di-isobutylaluminum hydride (1.0M in heptane, 15 ml, 15 mmol) wasadded, under nitrogen, to a stirred solution of the azidoactone (11)(3.99 g, 12.75 mmol) in dry THF (20 ml) at -70° C. After an additional 1h at -70° C., the solution was allowed to stand for 6 h at -20° C. when¹ H NMR indicated complete lactol formation. Sodium fluoride (0.5 g, 12mmol), saturated aqueous ammonium sulphate (2 ml), and ether (40 ml)were added sequentially whereupon a white galatinous precipitate formed.The mixture was filtered and the precipitate washed with ether (2×20ml). The filtrate and washings were combined, dried (magnesium sulphate)and the solvent removed to afford2-azido-2-deoxy-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptose(17). A small amount of material was recrystallized (ether), to give awhite crystalline solid, m.p. 114°-115° C. (Found: C, 49.82; H, 6.99; N,12.99. D₁₃ H₂₁ O₆ N₃ requires: C, 49.52; H, 6.71; N, 13.32%); [α]_(D20)+0.41° (C 1.0 in CHCl₃); ν_(max) (KBr) 3400 (br, OH), 2120 (N₃) cm⁻¹ ;δ_(H) (CDCl₃) 1.38 (6H, s, 2×Me), 1.43, 1.48 (6H, 2×s, 2×Me), 3.16 (1H,d, OH, D₂ O exch., J₁,OH 3.1 Hz), 3.54 (1H, dd, H-2, J₁,2 6.8 Hz, J₂,32.6 Hz), 3.62 (1H, dd, H-5, J₄,5 1.6 Hz, J₄,6 7.9 Hz), 4.00 (1H, dd,H-7, J₆,7 4.3 Hz, J₇,7' 8.7 Hz), 4.01 (1H, dd, H-7', J₆,7' 6.0 Hz), 4.22(1H, ddd, H-6), 4.45 (1H, dd, H-4, J₃,4 7.8 Hz), 4.60 (1H, dd, H-3),5.26 (1H, dd, H-1); δ_(C) (CDCl₃) 24.8, 25.6, 26.7 (3×q, 4×Me), 60.9 (d,C-2), 66.6 (t, C-7), 70.8, 72.8, 73.4, 73.6 (4×d, C-3, C-4, C-4, C-5,C-6), 92.7 (d, C-1), 109.7, 110.8 (2×s, 2×CMe₂); m/z (NH₃, DCI) 333(M+NH₄₊, 35%, 316 (M+H⁺, 25%), 288 (M+H⁺ --N₂, 100%).

Example 9

2-Azido-2-deoxy-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol(18). The remainder of the crude lactol (17) was dissolved in methanol(20 ml) and sodium borohydride (530 mg, 14 mmol) was added over 30 minat 0° C. After an additional 1 h at 0° C. the reaction was allowed towarm to room temperature and stirred for a further 1 h. at which pointt.l.c. (hexane:ethyl acetate, 1:1) indicated complete consumption of thelactol (17) (R_(f) 0.6) to give a single product (R_(f) 0.5). Thereaction was quenched by addition of saturated aqueous ammonium sulphate(2 ml). Flash chromatography (hexane:ethyl acetate, 3:1) gave2-azido-2-deoxy-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol(18) (3.16 g, 78% over two steps from (11)), a white crystaline solid,m.p. 74°-75° C. (ether/hexane). (Found: C, 49.14; H, 7.41; N, 13.03. C₁₃H₂₃ N₃ O₆ requires: C, 49.20; H, 7.31; N, 13.24%); [α]_(D20) -45.0° (c1.1 in CHCl₃); ν_(max) (CHCl₃): 3550 (OH), 2110 (N₃) cm⁻¹ ; δ_(H)(CDCl₃) 1.37, 1.38, 1.44, 1.50 (12H, 4×s, 4×Me), 2.01 (1H, dd, HO-1,J_(OH),1 5.1 Hz, J_(OH),1' 7.0 Hz), 2.18 (1 H, d, HO-5, J_(OH),5 9.5Hz), 3.8-4.1 (7H, m), 4.15 (1H, dd, J 6.9 Hz, J 9.6 Hz) 4.45 (1H, d, J6.9 Hz); δ_(C) (CDCl₃) 24.3, 25.1, 26.3, 26.6 (4×q, 4×Me), 61.3 (d,C-2), 63.5, 66.7 (2×t, C-1, C-7), 69.5, 74.9, 75.2, 73.3 (4×d, C-3, C-4,C-5, C-6), 108.9, 109.4 (2×s, 2×CMe₂); m/z (NH₃, DCI) 335 (M+NH₄₊, 10%),318 (M+H⁺, 20%), 290 (M+H⁺ --N₂, 100%).

Example 10

2-Azido-1-O-tert-butyldiphenylsilyl-2-deoxy-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol(19). tert-Butyldiphenylsilylchloride (0.55 ml, 2.12 mmol) was added,under nitrogen, to a stirred solution of the diol (18) (612 mg, 1.93mmol) and imidazole (263 mg, 3.8 mmol) in dry DMF at 0° C. The solutionwas then warmed to room temperature and stirred for 5 h, when t.l.c.(hexane:ethyl acetate, 3:1) showed only a trace of starting material(R_(f) 0.3) and one major product (R_(f) 0.7). The solvent was removed,the residue shaken with dichloromethane (30 ml) and then filtered.Evaporation and purification by flash chromatography (hexane:ethylacetate, 4:1) gave2-azido-1-O-tert-butyldiphenylsilyl-2-deoxy-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol(19) (983 mg, 92%), a viscous oil; [α]_(D20) -35.0° (c 1.05 in CHCl₃);ν_(max) (film) 3500 (br, OH), 2125 (N₃) cm⁻¹ ; δ_(H) (CDCl₃) 1.09 (9H,s, Me₃ C), 1.34, 1.38, 1.41, 1.45 (12H, 4×s, 4×Me), 2.13 (1H, d, OH,J_(OH),5 9.1 Hz, D₂ O exch.), 3.91 (3H, m), 4.05 (4H, m), 4.23 (1H, dd,J 6.9 Hz, J 9.6 Hz), 4.44 (1H, d, J 6.9 Hz), 7.43 (6H, m), 7.73 (4H, m);δ_(C) (CDCl₃) 19.0 (s, CMe₃), 24.3, 25.3, 26.4 (3×q, 3×Me), 26.5 (q,CMe₃), 26.7 (q, Me), 61.2 (d, C-2), 64.9, 66.9 (2×g, C-1, C-7), 69.6,74.0, 75.3, 76.4 (4×d, C-3, C-4, C-5, C-6), 108.7, 109.4 (2×s, 2×CMe₂),127.9, 129.9 (2×d, 2×Ar-C), 133.0 (s, Ar-C), 135.8 (d, Ar-C); m/z (NH₃,DCI) 528 (M+H⁺ --N₂, 20%), 510 (M+H⁺ --N₂ --OH₂, 100%).

Example 11

2-Azido-1-O-tert-butyldiphenylsilyl-2-deoxy-3,4:6,7-di-O-isopropylidene-D-glycero-D-talo-heptitol(20). Methanesulphonyl chloride (0.20 ml, 2.0 mmol) was added, undernitrogen, to a stirred solution of the alcohol (19) (447 mg, 0.81 mmol)and 4-N,N-dimethylaminopyridine (20 mg, 0.16 mmol) in dry pyridine (5ml) at room temperature. After 12 H, t.l.c. (hexane:ethyl acetate, 3:1)indicated complete consumption of starting material (R_(f) 0.6) to givea single product (R_(f) 0.5). The solvent was removed and the residuedissolved in chloroform (50 ml), washed with water (2×30 ml) and dried(magnesium sulphate). Removal of the solvent followed by flashchromatography (hexane:ethyl acetate, 6:1) gave2-azido-1-O-tert-butyldiphenylsilyl-2-deoxy-3,4:6,7-di-O-isopropylidene-5-O-methanesulphonyl-D-glycero-D-talo-heptitol (20)(458 mg, 90%), a white crystalline solid, m.p. 90°-91° C. (Found C,56.70; H, 6.85; N, 6.86. C₃₀ H₄₃ N₃ O₈ SSi requires c, 56.85; H, 6.84;N, 6.63%); [α]_(D20) -45.3° (c 1.0 in CHCl₃); ν_(max) (film) 2108 (N₃)cm⁻¹ ; δ_(H) (CDCl₃) 1.09 (9H, s, Me₃ C), 1.39, 1.44, 1.48, 1.57 (12H,4×s, 4×Me), 3.06 (3H, s, MeSO₃), 3.9-4.1 (4H, m), 4.13 (1H, dd, J 6.2Hz, J 8.8 Hz), 4.3 (2 H, m), 4.38 (1H, dd, J 1.9 Hz, J 6.2 Hz), 5.15(1H, dd, H-5, J 1.8 Hz, J 4.9 Hz), 7.43 (6H, m), 7.71 (4H, m); δ_(C)(CDCl₃) 19.00 (s, CMe₃), 25.0, 25.4, 26.0, 26.2 (4×q, 4×Me), 26.5 (q,CMe₃), 39.8 (q, MeSO₃), 59.5 (d, C-2), 64.6, 75.8 (2×t, C-1, C-7), 74.0,75.5, 76.0, 77.7 (4×d, C-3, C-4, C-5, C-6), 109.4, 110.2 (2×s, 2×CMe₂),128.0, 130.2 (2×d, 2×Ar-C), 133.0 (s, Ar-C), 136.0 (d, Ar-C); m/z (NH₃,DCI) 651 (M+NH₄₊, 30%), 606 (M+H⁺ --N₂, 100%).

Example 12

2-Azido-1-O-tert-butyldiphenylsilyl-2-deoxy-3,4-O-isopropylidene-5-O-methanesulphonyl-D-glycero-D-talo-heptitol(21). The diacetonide (20) (463 mg, 0.73 mmol) was dissolved in1,4-dioxan (3 ml) and 80% aqueous acetic acid (6 ml) was then added. Thereaction was stirred at 50° C. for 1.5 h when t.l.c. (hexane:ethylacetate, 2:1) showed only a trace of starting material (R_(f) 0.8), amajor product (R_(f) 0.3) and a minor product (R_(f) 0.1). The solventwas removed at 20° C. and the residue co-evaporated with toluene (3×5ml). Purification by flash chromatography (hexane:ethyl acetate, 1:1)gave three products; the first to be eluted was unreacted startingmaterial (20) (14 mg, 3%); the second fraction was the diol,2-azido-1-O-tert-butyldiphenylsilyl-2-deoxy-3,4-O-isopropylidene-5-O-methanesulphonyl-D-glycero-D-talo-heptitol(21) (344 mg, 79%), a viscous oil. (Found: C, 54.71; H, 6.94; N, 6.91.C₂₇ H₃₉ N₃ O₈ SSi requires C, 54.61; H, 6.62; N, 7.08%); [α]_(D20)-40.5° (c 1.0 in CHCl₃); ν_(max) (film) 3450 (br, OH), 2110 (N₃) cm⁻¹ ;δ_(H) (CDCl₃) 1.09 (9H, s, Me₃ C), 1.33, 1.35 (6H, 2×s, 2×Me), 2.7 (1H,br. s, OH), 3.13 (3H, s, MeSO₃), 3.65 (1H, br. s, OH), 3.8 (5H, m), 4.10(1H, m), 4.21 (1H, dd, J 5.6 Hz, J 10.0 Hz), 4.46 (1H, t, J 5.5 Hz),5.16 (1H, t, H-5, J 5.5 Hz), 7.43 (6H, m), 7.70 (4H, m); δ_(C) (CDCl₃)19.0 (s, CMe₃), 25.4 (q, CMe₃), 26.7 (q, CMe₂), 39.3 (q, MeSO₃), 60.1(d, C-2), 62.1, 64.9 (2×t, C-1, c-7), 72.9, 74.7, 76.6, 78.4 (4×d, C-3,C-4, C-5, C-6), 109.5 (s, CMe₂), 127.9, 130.0 (2×d, 2×Ar-C), 132.8 (s,Ar-C), 136.0 (d, Ar-C). Continued elution yielded the tetrol,2-azido-1-O-tert-butyldiphenylsilyl-2-deoxy-5-O-methanesulphonyl-D-glycero-D-talo-heptitol(16 mg, 4%), a viscous oil which rapidly decomposed, δ_(H) : 1.09 (9H,s, Me₃ C), 3.13 (3H, s, MeSO₃), 3.5-3.9 (8H, m), 4.04 (4H, m), 4.98 (1H,d, H-5, J 6.2 Hz), 7.44 (6H, m), 7.69 (4H, m); δ_(C) 18.9 (s, CMe₃),26.6 (q, CMe₃), 38.2 (q, MeSO₃), 62.3, 63.9 (2×t, C-1, C-7), 64.9 (d,C-2), 70.2, 70.6, 71.4, 79.2 (4×d, C-3, C-4, C-5, C-6), 128.1, 130.2(2×d, 2×Ar-C), 132.6 (s, Ar-C), 135.7 (d, ArC).

Example 13

5,6-Anhydro-2-azido-1-O-tert-butyldiphenylsilyl-2-deoxy-3,4-O-isopropylidene-D-glycero-L-allo-heptitol(22). Saturated methanolic barium methoxide solution (0.5 ml) was addedto a stirred solution of the diol (21) (457 mg, 0.77 mmol) in drymethanol (5 ml) at 0° C. After 30 min at room temperature, t.l.c.(hexane:ethyl acetate, 1:1) indicated no starting material (R_(f) 0.25)and a single product (R_(f) 0.5). The solution was filtered, a smallamount of solid carbon dioxide added to the filtrate and the solventremoved. Flash chromatography (hexane:ethyl acetate, 4:1) gave5,6-anhydro-2-azido-1-O-tert-butyldiphenylsilyl-2-deoxy-3,4-O-isopropylidene-D-glycero-L-allo-heptitol(22) (354 mg, 925), a colourless oil. (Found: C, 62.74; H, 7.27; N,8.14. C₂₇ H₃₉ N₃ O₈ SiS requires C, 62.75; H, 7.09; N, 8.44%); [α]_(D20)-12.3° (c 1.0 in CHCl₃); ν_(max) (film) 3450 (br, OH) cm⁻¹ ; δ_(H)(CDCl₃) 1.10 (9H, s, Me₃ C), 1.30, 1.36 (6H, 2×s, 2×Me), 1.70 (1H, br s,OH), 3.20 (2H, m, H-5, H-6), 3.63 (1H, ddd, H-2, J₁,2 2.8 Hz, J_(1'),26.8 Hz, J₂,3 9.7 Hz), 3.74 (1H, m, H-7), 3.90 (1H, dd, H-1', J₁,1' 10.8Hz), 4.00 (1H, br d, H-7'), 4.02 (1H, t, H-4), 4.06 (1H, dd, H-1), 4.15(1H, dd, H-3, J₃,4 5.7 Hz), 7.46 (6H, m), 7.73 (4H, m); δ_(C) (CDCl₃)19.0 (s, CMe₃), 25.0 (q, Me), 26.5 (q, CMe₃), 27.5 (q, Me), 52.2, 56.5(2×d, c-5, C-6), 61.0, 64.9 (2×t, C-1, C-7), 61.6 (d, C-2), 75.2, 77.0(2×d, C-3, C-4), 109.5 (s, CMe₂), 127.9, 130.0 (2×d, 2×Ar-C), 133.0 (s,Ar-C), 135.8 (d, Ar-C); m/z (NH₃, DCI) 470 (M+H⁺ --N₂, 100%).

Example 14

5,6-Anhydro-2-azido-7-O-tert-butyldimethylsilyl-1-O-tert-butyldiphenylsilyl-2-deoxy-3,4-O-isopropylidene-D-glycero-L-allo-heptitol(23). tert-Butyldimethylsilyl chloride (122 mg, 0.81 mmol) was added,under nitrogen, to a stirred solution of the epoxyalcohol (22) (270 mg,0.54 mmol) and imidazole (120 mg, 1.76 mmol) in dry DMF (5 ml) at 0° C.The solution was allowed to warm to room temperature. After 2 h, t.l.c.(hexane:ethyl acetate, 1:1) showed only a trace of starting material(R_(f) 0.35) and one major product (R_(f) 0.8). The solvent was thenremoved and the residue dissolved in ether (10 ml), washed with water (5ml) and brine (2×5 ml), and dried (magnesium sulphate). Removal of thesolvent and purification by flash chromatography (hexane:ethyl acetate,6:1) gave5,6-anhydro-2-azido-7-O-tert-butyldimethylsilyl-1-O-tert-butyldiphenylsilyl-2-deoxy-3,4-O-isopropylidene-D-glycero-L-allo-heptitol(23) (280 mg, 84%), a viscous oil. [α]_(D20) -3.3° (c 0.55 in CHCl₃);ν_(max) (film) 2110 (N₃) cm⁻¹ ; δ_(H) (CDCl₃) 0.09 (6H, s, SiMe₂), 0.91,1.09 (18H, 2×s, 2×Me₃ C), 1.29, 1.36 (6H, 2×s, 2×Me), 3.11 (2H, br m,H-5, H-6), 3.66 (1H, ddd, H-2, J₁,2 2.8 Hz, J_(1'),2 6.7 Hz, J₂,3 9.6Hz), 3.75 (1H, dd, H-7', J₆,7 4.5 Hz, J₇,7 12.0 Hz), 3.88 (1H, dd, H-1',J_(1'),1 10.8 Hz), 3.93 (1H, dd, H-7, J₇,6 2.8 Hz), 4.01 (1H, t, H-4, J6.0 Hz), 4.05 (1H, dd, H-1), 4.14 (1H, dd, H-3, J₃,4 5.7 Hz); δ_(C)(CDCl₃) -5.50 (q, SiMe₂), 18.5, 19.0 (2×s, 2×CMe₃), 25.1 (q, Me), 25.7,26.6 (2×q, 2×CMe₃), 27.6 (q, Me), 52.3, 56.7 (2×d, C-5, C-6), 61.6 (d,C-2), 62.5, 65.1 (2×t, C-1, C-7), 73.5, 787.1 (2×d, C-3, C-4), 109.4 (s,CMe₂), 127.9, 130.0 (2×d, 2×Ar-C), 133.0 (s, Ar-C), 135.9 (d, Ar-C); m/z(NH₃, DCI) 584 (M+H⁺ --N₂, 50%).

Example 15

7-O-tert-Butyldimethylsilyl-1-O-tert-butyldiphenylsilyl-2,5-dideoxy-2,5-imino-3,4-O-isopropylidene-D-glycero-D-talo-heptitol(24). The silyl protected azidoepoxyalcohol (23) (150 mg, 0.409 mmol)and palladium black (7 mg) were stirred in ethanol (4 ml) at roomtemperature under hydrogen. After 24 h, t.l.c. (hexane:ethyl acetate,2:1) indicated complete consumption of starting material (R_(f) 0.8) togive a single product (R_(f) 0.35), the cyclised amine. The reactionmixture was filtered through a small celite pad, washing with ethanol,and the solvent removed to give a colourless oil. Purification by flashcolumn chromatography (hexane:ethyl acetate, 1:8) gave7-O-tert-butyldimethylsilyl-1-O-tert-butyldiphenylsilyl-2,5-dideoxy-2,5-imino-3,4-O-isopropylidene-D-glycero-D-talo-heptitol(24) (107 mg, 75%), a colourless oil. [α]_(D20) -11.0° (c 1.0 in CHCl₃);ν_(max) (film) 3200 (br OH & NH) cm¹ ; δ_(H) (CDCl₃) 0.08 (6H, s,SiMe₂), 0.89, 1.07 (18H, 2×s, 2×Me₃ C), 1.33, 1.50 (6H, 2×s, 2×Me), 2.02(br OH, NH), 3.14 (1H, dd, H-5, J₄,5 4.3 Hz, J₅,6 6.1 Hz), 3.34 (1H, t,H-2, J 6.2 Hz), 3.60 (4H, br m, H-1, H-1', H-7, H-7'), 3.86 (1, br m,H-6), 4.68 (1H, d, H-3, J₃,4 5.7 Hz), 4.75 (1H, dd, H-4), 7.39 (6H, m),7.65 (4H, m); δ_(C) (CDCl₃) -5.6 (q, SiMe₂), 18.1, 19.0 (2×s, 2×CMe₃),23.7, 25.7 (2×q, 2×Me), 25.9, 26.8 (2×q, 2×CMe₃), 62.2, 65.0 (2×d, C-2,C-5), 64.4, 65.8 (2×t, C-1, C-7), 71.6, 82.6, 83.6 (3×d, C-3, C-4, C-6),111.2 (s, CMe₂), 127.9, 129.8 (2×d, 2×Ar-C), 133.2 (s, Ar-C), 135.7 (d,Ar-C); m/z (NH₃, DCI) 586 (M+H⁺, 100%).

Example 16

α-HomoDIM [2,5-dideoxy-2,5-imino-D-glycero-D-talo-heptitol] (4). Thecyclised amine (24) 52 mg, 0.09 mmol) was stirred in trifluoroaceticacid:water, 1:1 (2 ml) for 48 h. Removal of the solvent and purificationby ion exchange chromatography with Dowex 50W-X8 (H⁺) then gave, afterfreeze drying, the free base as a gum. Addition of dilute hydrochloricacid and freeze drying gave the hydrochloride salt of2,5-dideoxy-2,5-imino-D-glycero-D-talo-heptitol (4) (16 mg, 78%), m.p.148°-149° C. (methanol/chloroform). (Found D, 36.30; H, 7.25; N, 5.83.C₇ H₁₆ NO₅ Cl requires C, 36.60; H, 7.02; N, 6.09%); [α]_(D20) +26.9° (c1.0 in H₂ O); ν_(max) (KBr disc) 3350 (broad OH & NH), 2950 cm⁻¹ ; δ_(H)(D₂ O) 3.59 (3H, m, H-2, H-5, H-7), 3.67 (1H, dd, H-7', J₇,7' 12.1 Hz,J_(7'6) 4.2 Hz), 3.76 (1H, dd, H-1, J₁,1' 12.6, J₁,2 3.8 Hz), 3.88 (1H,dd, H-1', J_(1'2) 3.3 Hz), 4.02 (1H, m H-6), 4.17 (1H, dd, H-4, J₃,4 3.7Hz, J₄,5 9.3 Hz), 4.33 (1H, br t, H-3); δ_(C) (D₂ O) 59.2, 62.1 (2×d,C-2, C-5), 63.3, 63.7 (2×t, C-1, C-7), 68.4, 71.5, 72.2 (3×d, C-3, C-4,C-6); m/z (NH₃, DCI) 194 (M+H⁺, 100%).

REFERENCES

¹ Winchester, B, and Fleet, G. W. J., Glycobiology, 1992, 2, 199;Legler, G., Adv. Carbohydr. Chem. Biochem., 1990, 48, 319.

² Furui, H., Kiso, M., and Hasegawa, A., Carbohydr. Res., 1992, 229, C1.

³ Rhinehart, B. L., Robinson, K. M., King, C. H., and Liu, P. S.,Biochem. Pharmacol., 1990, 39, 1537; Liu, P. S., J. Org. Chem., 1987,52, 4717.

⁴ B. Woynarowska, B., Wilkiel, H., Sharma, M., Carpenter, N., Fleet, G.W. J., and Bernacki, R. J., Anticancer Res., 1992, 12, 161; Liu, P. S.,Kang, M. S., and Sunkara, P. S., Tetrahedron Lett., 1991, 32, 719.

⁵ Jones, I. M., and Jacob, G. S., Nature, 1991, 330, 74; Taylor, D. L.,Sunkara, P. S., Liu, P. S., Kang, M. S., Bowlin, T. L. and Tyms, A. S.,AIDS, 1991, 5, 693; Stephens, E. G., Monck, E., Reppas, K., andButfiloski, E. J., J. Virol., 1991, 65, 1114.

⁶ Lees, W. J. and Whiteside, G. M., Bioorg. Chem., 1992, 20, 173;Hassan, M. E., Gazz. Chim. Ital., 1992, 122, 7; Fairbanks, A. J.,Carpenter, N. M., Fleet, G. W. J., Ramsden, N. G., Cenci de Bello, I.,Winchester, B. G., Al-Daher, S. S., and Nagahashi, G., Tetrahedron,1992, 48, 3365.

⁷ Burgess, K., and Henderson, I., Tetrahedron, 1992, 48, 4045;St.-Denis, Y., and Chan, T. H., J. Org. Chem., 1992, 57, 3078; Herczegh,P., Kovacs, I., Szilagyi, L., Zsely, M., and Sztaricskai, F.,Tetrahedron Lett., 1992, 33, 3133; Gradnig, G., Berger, A., Grassberger,V., Stuetz, A. E., and Legler, G., Tetrahedron Lett., 1991, 32, 4889.

⁸ Bischoff, J., and Kornfeld, R., Biochem. Biophys, Res. Commun., 1984,125, 324; Fuhrmann, U., Bause, E., Legler, G., and Ploegh, H., Nature,1984, 307, 755.

⁹ de Gasperi, R., Daniel, P. F., and Warren, C. D., J. Biol. Chem.,1992, 267, 9706.

¹⁰ White, S. L., Nagai, T., Akiyama, S. K. Reeves, E. J. Grzegorzewski,K., and Olden, K., Cancer. Commun., 1991, 3, 83; Olden, K., Breton, P.,Grzegorzewski, K., Yasuda, Y., Gause, B. L., Oredipe, O. A., Newton, S.A., and White, S. L., Pharmacol. Ther., 1991, 50, 285.

¹¹ Fleet, G. W. J., Ramsden, N. G., and Witty, D. R., Tetrahedron, 1989,45, 319.

¹² Carpenter, N. M., Fleet, G. W. J., and Cenci di Bello, I.,winchester, B., Fellows, L. E., and Nash, R. J., Tetrahedron Lett.,1989, 30, 7261.

¹³ Beacham, A. R., Bruce, I., Choi, S., Doherty, O., Fairbanks, A. J.,Fleet, G. W. J., Skead, B. M., Peach, J. M., Saunders, J., and Watkin,D. J., Tetrahedron: Asymm., 1991, 2, 883.

¹³ Choi, S., Bruce, I., Fairbanks, A. J., Fleet, G. W. J.,, Jones, A.H., Nash, R. J., and Fellows, L. E., Tetrahedron Lett., 1991, 32, 5517.

¹⁵ Mantell, S. J., Fleet, G. W. J., and Brown, D., Tetrahedron Lett.,1992, 33, 4503.

¹⁶ Fleet, G. W. J., Bruce, I., Firdnar, A., Harladsson, M., Peach, J.M., and Watkins, D. J., Tetrahedron, 1990, 46, 19.

¹⁷ Denci di Bello, I., Fleet, G., Namgoong, S.-K., Tadano, K.-I., andWinchester, B., Biochem. J., 1989, 259, 855.

¹⁸ Winchester, B. G., Cenci di Bello, I., Richardson, A. C., Nash, R.J., Fellows, L. E., Ramsden, N. G., and Fleet, G., Biochem. J., 1990,269, 227.

¹⁹ Dumas, D. P., Kajimoto, T., Liu, K. K.-C., Wong, W.-H, Berkowitz, D.B., and Danishefsky, S. J., Bioorg. Med. Chem. Lett., 1992, 2, 33.

Various other examples will be apparent to the person skilled in the artafter reading the present disclosure without departing from the spiritand scope of the invention. It is intended that all such other examplesbe included within the scope of the appended claims.

What is claimed is:
 1. 2,5-Dideoxy-2,5-imino-D-glycero-D-talo-heptotol.2. A method for the synthesis of1,5-dideoxy-2,5-imino-D-glycero-D-Talo-heptitol (4) comprising carryingout the reactions in solution phase and in about stoicheometricproportions of reactants shown by formulas in the following reactionsteps:a. reducing2-azido-2-deoxy-3,4:5,6-di-O-isopropylidene-D-glycero-D-talo-heptono-1,5lactone(11) with di-isobutylaluminum hydride to give the corresponding lactol(17), ##STR10## b. reacting the lactol (17) with alkali metalborohydride to provide ring opening and give the diol (18), ##STR11## c.reacting the diol (18) with tert-butyldiphenyl-silylchloride to protectthe primary hydroxyl group as the tert-butyldiphenylsilyl ether (19),##STR12## d. esterifying the hydroxyl of the tert-butyldiphenylsilylether (19) at C-5 with mesyl chloride to give azidomesylate (20),##STR13## e. selectively hydrolyzing the terminal acetonide at C-6, C-7in the azidomesylate (20) with organic acid to give monoacetonide (21),##STR14## f. reacting the monoacetonide (21) with barium methoxide togive epoxide (22), ##STR15## g. reacting the epoxide (22) withtert-butyldimethylsilylchloride to protect the primary hydroxyl group asthe tert-butyldimethylsilyl ether (23), ##STR16## h. hydrogenating thetert-butyldimethylsilyl ether (23) in the presence of palladium black togive the protected pyrrolidine (24), and ##STR17## i. removing all thehydroxyl protecting groups in the protected pyrrolidine (24) by acidhydrolysis to give the desired2,5-dideoxy-2,5-imino-D-glycero-D-talo-heptitol (4) ##STR18##